A counter-current flow micro-packed-bed DBD plasmatron for the synthesis of a methylated cobaloxime

Yukun Liu, Jasmine C. Sabio, Ryan L. Hartman

Research output: Contribution to journalArticlepeer-review


An atmospheric, dielectric-barrier discharge µ-plasmatron was designed, fabricated, and applied to synthesize a methylated organometallic complex. The design comprises counter-current flow to packed-bed microstructures to facilitate gas-liquid and plasma-liquid mixing. Micropillars arranged in a staggered configuration served as a porous media for the optimum 2D mixing of components that replenish plasma-liquid interfaces. Longitudinal dispersion was characterized through residence time distribution (RTD) measurements. The experimental RTD data were then described by an axial dispersion model with a time delay parameter. Levenspiel number (lv) indicating the intensity of axial dispersion was estimated in the range of 20.1-374, indicating that a dispersion model should be accounted for in plasma-assisted reaction kinetics development. Stable plasma excitation of methane-helium gas mixtures was observed within the 2D porous media, by in-situ optical emission spectra, while applying an alternating high voltage across the dielectric barrier. This novel technique made it possible to confirm in-situ formations of methyl radicals. Interestingly, the porous media served as a static mixer as no discrete plasma streamers were observed. To investigate its utility, an example homogeneous cobalt catalyst was injected into the µ-plasmatron and methylated. Our findings potentially introduce a new plasma-assisted reactor design and methodology for the synthesis of methylated cobaloxime.

Original languageEnglish (US)
Article number194003
JournalJournal of Physics D: Applied Physics
Issue number19
StatePublished - May 13 2021


  • dispersion
  • methylation
  • multiphase flow
  • non-thermal plasma
  • plasma catalysis

ASJC Scopus subject areas

  • Electronic, Optical and Magnetic Materials
  • Condensed Matter Physics
  • Acoustics and Ultrasonics
  • Surfaces, Coatings and Films


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